Silva, V.N. da, Silva, L.E. de S.F. da, Figueiredo, M. do V.B., Carvalho, F.G. de, Silva, M.L.R.B. da and Silva, A.J.N. da 2007. CHARACTERIZATION AND SELECTION OF NATIVE POPULATIONS OF SOIL RHIZOBIA OF THE SEMI-ARID REGION OF PERNAMBUCO, BRAZIL. Pesquisa Agropecuária Tropical [Agricultural Research in the Tropics]. 37, 1 (Oct. 2007), 16–21.